The invention described here may be made, used and licensed by the United States Government for governmental purposes without paying me any royalty.
Robotic vehicles are becoming more prevalent in a wide variety of situations where it is desirable to minimize the exposure of humans to dangerous conditions. Commercial environments include hazardous chemical materials and nuclear materials where exposure by humans must be avoided. The military desires to use robotic devices as a means of probing into surrounding territory for the purposes of reconnaissance and force projection without the need to expose its valuable and highly trained troops. Thus, a military robotic vehicle might be equipped with sensors for identifying hostile forces, measuring terrain variables and deploying obstacles. A military robot may also carry one or more forms of munitions to protect the robot and to remove obstacles encountered by the robot.
One important characteristic for robotic vehicles used in military applications is the ability to operate in soft soils. A second important aspect is stability of the vehicle as it traverses uneven terrain. Yet another aspect is the quality of traction provided by the drive units of the vehicle. The drive units used must have limited skid or slip when driving the vehicle even in soft soil or uneven terrain.
At present, many robotic structures are modeled on multiple wheeled structures such as small cars. Such vehicles have problems with soft soil conditions where the wheels tend to become mired and the vehicle will become disabled due to the high pounds per square inch tire footprint. Also, such multi wheeled vehicles require a complex steering and control system making fabrication difficult and expensive. A multi wheeled structure also results in a high center of gravity when the vehicle is carrying weapons or sensors above the vehicle.
A second type of robotic vehicle is designed with various combinations of multi-legged structures to form a spider configuration. Spider configurations can move over small obstacles; however, such devices require complex control technology and are very slow moving since each leg must be moved individually. Such structures have a high center of gravity and are not well adapted to carry a load. Multi-tracked devices have also been proposed. Track laying devices also require complex control systems and the vehicle""s ability to maneuver is dependent on chassis width of the vehicle and the length of the track.
It is an object of this invention to provide a robotic vehicle, which has a relatively low center of gravity even when carrying weapons, and or sensing devices. It is a further object of this invention to provide a robotic vehicle with good traction over a variety of various terrains. Further, it is an object of this invention that the robotic vehicle be able to maneuver in a relatively small area so as to provide sensing and targeting direction without substantial vehicle movement.
These and other objects are accomplished by a robotic according to this invention. The robotic vehicle has an elliptical shaped housing with major and minor axes, the elliptical housing having its major axis substantially parallel to the terrain the vehicle is traversing. The elliptical housing has a continuous circumferential track disposed about its midsection coaxial with the major axis of the elliptical housing. The circumferential track has a ground gripping texture on its outer surface to ensure good traction for the robotic vehicle over an extremely wide variety of soil and terrain conditions.
The robotic vehicle of this invention has an axle mounted along the elliptical housing major axis. The axle is journaled with the housing to allow the housing and axle to rotate freely with respect to one another during operation as is described in detail below. The axle serves as a principal means of support for vehicle systems and serves to consolidate the various parts of the robotic structure. Many of the parts of the vehicle will be attached to the axle and use it to function together.
The robotic vehicle has a prime mover mounted within the elliptical housing to provide power to rotate the elliptical housing about the major axis and also provide the power to operate other functions attached to the vehicle. The prime mover is suspended from the axle and depends downward from the axle towards the ground to a position below the axle and near the ground. Placing the prime mover low in the housing results in a lowered center of gravity for the entire housing and thereby the vehicle.
The prime mover is engaged with a transmission that transmits power to the system. The transmission comprises a first drive gear connected to the prime mover the first gear in turn engaging a second, larger internally toothed gear, the two gears forming an internal spur gear drive combination. The larger gear of the power transmission is engaged with the continuous circumferential track so that as the large gear rotates, the circumferential track will rotate about the axle of the housing.
In addition to the prime mover-power transmission-circumferential track drive mechanism, the robotic system of this invention has a compressed gas steering system located within the elliptical housing. The compressed gas steering system includes a compressor that draws power from the prime mover and delivers ambient air under pressure to a gas storage tank for storage and later use. Sensing means will activate the compressor to maintain the desired pressure in the gas storage tank. A gas delivery system is connected to the gas storage tank for the delivery system having gas lines fluidly connected to the storage tank, with control valves as part of the delivery system. The delivery system provides compressed air to the rest of the system as needed. The compressed air system has jet nozzles located on each end of the axle; the jets have control means to change their orientation to provide additional steering and maneuverability. The control valves in the gas delivery system provide the required amounts of compressed air to the jets when it is desired to effect a rapid or tight radius turn.
Braking members are provided which can apply a braking force to the axle to promote turning, control speed, and hold the robot in position for firing of its weapons. The brakes can also be used to hold the robot in a fixed position for reconnaissance and use as a remote sensing station.
The second major portion of the overall robotic weapons system of this invention is a platform adapted to carry weapons and/or other functional units such as sensors, and communication units. The platform containing the desired items is supported by and journaled on the axle of the housing. The platform has a load-carrying surface located above the elliptical housing with respect to the surface on which the housing is located. The load-carrying surface is used to support the various mission critical gear that is needed to determine the terrain and locate possible military targets within the range of the robot. The load-carrying surface may also carry a radio antenna, and receiving devices for global positioning systems and other electronic equipment.
The weapons portion of the present system of this invention includes weapons pods mounted on the ends of the axle. The weapons pods will have a positioning motor that can rotate the weapons pod about the axle to the desired angle of elevation for firing.
Counterweight shells are attached to the axle opposite the weapons platform. The counterweight shells are adapted to carry a portion of the electronic systems, which will conserve volume and provide additional weight to the compounds. The shells will also contains a quantity of liquid to provide an adjustable component to the ballast for the weapons system.
The robotic vehicle has a liquid control system, which includes a pump, fluid lines and valves. The liquid control system fluidly connects the counterweight shells and is responsive to signals from the vehicle control means to move liquid between the counterweights. This will change the balance of the elliptical housing with respect to the circumferential tread in order to effect the robot""s direction of travel.